When protecting a building from flooding, the best flood barrier needs verified performance and a design suited to its opening. Garrison Flood Control's Hammerhead® Aluminum Flood Plank System is an FM Approved flood barrier for building openings, offering an independently evaluated option for property owners, engineers, and facility managers.
On October 19, 2026, Hammerhead received FM Approval under FM 2510, with Approval Identification PR472193. The approval applies to specified Hammerhead configurations, not every possible system size or installation.
What Does FM Approval Mean for a Flood Barrier?
FM Approval is an independent product certification issued by FM Approvals. For flood mitigation equipment, the FM 2510 examination standard evaluates whether qualifying products meet defined performance requirements.
Buyers gain third-party evidence beyond manufacturer claims.
Approval also involves continuing oversight. FM Approved manufacturers are subject to surveillance audits, manufacturing controls, and requirements that production products remain consistent with the approved design. This creates an additional layer of confidence when evaluating long-term flood protection.
How Was Hammerhead Evaluated Under FM 2510?
Garrison's published approval announcement describes several important elements of the FM 2510 evaluation:
Water pressure and leakage: Hydrostatic testing assesses resistance to standing water, including a minimum 20-hour hold at maximum design water depth under the standard.
Debris impact: Opening barriers are evaluated against dynamic impacts, including two impacts of 600 joules each, to assess whether impact damage compromises functionality.
Leakage limits: FM 2510 opening barriers must meet a leakage limit of no more than 0.08 gallons per hour per linear foot of seal.
Deployment and construction: Evaluations also consider installation procedures, components, documentation, and conformity to the tested design.
FM Approvals' report confirms the specified Hammerhead models met applicable FM 2510 examination and testing requirements. Approval does not mean that a barrier is completely watertight under every possible flood condition.
Which Hammerhead Flood Barrier Configurations Are FM Approved?
The official FM Approval listing identifies two manually deployed opening-barrier configurations:
| Approved Hammerhead Model | Maximum Approved Opening Width | Maximum Approved Water Depth |
|---|---|---|
| 96" W × 36" H | 8 feet | 2.88 feet |
| 40" W × 65" H | 3.33 feet | 5.33 feet |
Both listings allow approved jamb-mount or exterior face-mount installations, subject to the specified instructions and construction details.
These figures are approval limits, not general limits for every Hammerhead product. Other sizes are available from Garrison depending on your protection needs.
Why Choose the Hammerhead Aluminum Flood Plank System?
Durable Materials and Purpose-Built Seals
Hammerhead uses extruded 6063-T6 aluminum planks and posts, with 316L marine-grade stainless steel hardware. The evaluated design uses EPDM rubber gaskets between the planks, channels, and ground, plus foam seals against the mounting wall.
These components are designed to create a reusable physical barrier across a vulnerable opening while limiting water intrusion.
Removable Planks for Practical Flood Preparation
Hammerhead operates as a demountable, stackable flood barrier. Vertical mounting channels remain in place; when flooding threatens, users insert the aluminum planks, stack them to the required height, and secure the assembly following the installation and deployment instructions.
When not needed, the planks can be removed and stored, restoring access to the opening. This makes Hammerhead useful for properties that need protection without a permanently closed doorway or entryway.
Enhanced Sealing Options
Garrison also offers its SureGasket™ and AlumiSeal™ sealing technologies to help address leakage at critical junctions, including where the bottom plank meets the ground and mounting channels.
Where Is an FM Approved Flood Barrier Most Useful?
Hammerhead is particularly relevant to owners evaluating flood protection for entrances, service doors, and other building openings at residences, commercial buildings, and facilities.
However, the FM 2510 opening-barrier listing covers riverine and rainfall-related flooding. Site-specific engineering, mounting conditions, expected water depth, and proper deployment remain critical.
The best selection process starts by matching the property's flood exposure and opening dimensions to the barrier's actual approved rating, rather than choosing on height or appearance alone.
A Strong Choice for Independently Verified Flood Protection
For customers seeking an FM Approved aluminum flood barrier, Hammerhead combines third-party evaluation with reusable aluminum construction and removable, stackable deployment. Its October 2026 certification adds an important credential to Garrison Flood Control's engineered flood protection offering.
Explore the Hammerhead Aluminum Flood Plank System, review the FM Approval announcement, or contact Garrison Flood Control to discuss a project.
Frequently Asked Questions About FM Approved Flood Barriers
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The best choice depends on site dimensions and flood exposure. Hammerhead is FM Approved for qualifying opening-barrier applications in two configurations.
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Yes. On October 19, 2026, FM Approvals certified two specific configurations under FM 2510, Approval ID PR472193.
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FM 2510 includes evaluations of water pressure, leakage, debris impact, deployment, product documentation, and manufacturing conformity.
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The approved models are 96 × 36 inches and 40 × 65 inches, rated for maximum water depths of 2.88 and 5.33 feet, respectively.
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Yes. Inspection and maintenance according to Garrison's instructions remain necessary, as does proper deployment before flooding.